public void processData(EntityPlayer entityPlayer, ByteBufInputStream bbis) throws IOException {
      ItemStack itemStack = entityPlayer.getHeldItem();
      if (itemStack != null) {
         boolean incDmg = bbis.readBoolean();
         int maxDmg = 15;
         int itemDmg = itemStack.getItemDamage();
         itemDmg += incDmg ? 1 : -1;
         if (itemDmg > maxDmg) {
            itemDmg = 0;
         } else if (itemDmg < 0) {
            itemDmg = maxDmg;
         }

         itemStack.setItemDamage(itemDmg);
      }

   }